(1) Field of the Invention
The present invention relates to a method of producing a preform wire for a fiber reinforced metal composite and an ultrasonic wave vibration apparatus used in the method. More particularly, the present invention relates to a method of producing a light, elastic and strong preform wire for a fiber reinforced metal composite, which wire is a silicon carbide fiber/metal composite material consisting of silicon carbide fibers and a metal fully penetrated between the fibers, and has no vacant space between the fibers; and an ultrasonic wave vibration apparatus which can vibrate efficiently a molten metal used in the method.
The term "preform wire for a fiber reinforced metal composite" used in the present invention includes not only preform wire for a fiber reinforced metal composite, but also preform sheet or tape for a fiber reinforced metal composite.
(2) Description of the Prior Art
A composite material consisting of a fibrous material, such as silicon carbide fiber or the like, impregnated with a metal, such as aluminum or the like, has excellent properties of both the metal and the fiber, and is tough, light and flexible. Therefore, the composite material is expected to be widely used as a material for vehicle, aircraft, rocket, spaceship and other various articles.
The have been proposed various methods in the production of the metal/fiber composite material. For example, there is known a method, such as plasma jet, metalikon or vapor deposition, wherein metal fine particle or metal vapor is blown against a fiber bundle to adhere the metal to the fiber surface and to produce a metal/fiber composite material or its precursor. However, in these methods, metal fine particle or metal vapor is straight blown to a fiber bundle, and therefor these methods have a drawback that the metal is not fully penetrated into the interior of the fiber bundle, and a composite material having satisfactorily high strength and elasticity can not be obtained.
Further, these has been proposed a method, wherein a fiber bundle is immersed in a molten metal bath and at the same time an ultrasonic wave vibration is given to the molten metal bath in order to penetrate the molten metal into the interior of the fiber bundle. In this method, the fiber bundle is unwoven by the ultrasonic wave vibration, and air contained in the interior of the fiber bundle is exhausted, and hence metal is fully penetrated into the interior of the fiber bundle, but the fibers are fixed in a randomly unwoven state by the vibration. Accordingly, it is difficult to produce in this method a metal/fiber composite material having desired strength and elasticity. Further, when an ultrasonic wave vibration apparatus is used, the vibrator cracks with the lapse of time from the wall forming the hole, which is formed in order to pass therethrough a water for cooling the horn of the vibrator, and hence the vibration is not transmitted to the horn end portion which is kept immersed in the molten metal bath.
As described above, there have not been known a method of producing a metal/fiber composite material which is light in weight and is excellent in strength and elasticity, nor an ultrasonic wave vibration apparatus to be advantageously used for the method.
The present invention aims to solve the above described problems and to provide a metal/fiber composite material, particularly a preform wire for a fiber reinforced metal composite, which consists of a metal, such as aluminum or the like, and silicon carbide fiber, and is lighter in weight and is more excellent in strength and elasticity than conventional metal/fiber composite materials, and to provide an ultrasonic wave vibration apparatus to be used in the method.
The inventors have made various investigations in order to attain the above described object, and found out that, when a silicon carbide fiber bundle is previously drawn such that the element fibers constituting the fiber bundle are uniformly arranged in a parallel relation along their length direction, is occasionally sprayed or deposited with a metal, such as aluminum or the like, and then the fiber bundle is immersed in a molten metal bath which is kept vibrated by means of an ultrasonic wave vibration apparatus, an excellent preform wire for a fiber reinforced metal composite can be obtained The inventors have further found out that, in order to protect an ultrasonic wave vibration apparatus used in the above described method from high temperature, when a hole for cooling water is formed in the horn of the vibrator, or a water-cooling jacket is arranged on the horn of the vibrator, at the upper portion, which is not immersed in the molten metal bath, and at the position corresponding to the node of the half-wavelength of the ultrasonic wave, a metal/fiber composite material having a stable property over a long period of time and being free from cracks in the horn during the use can be obtained. As a result, the inventors have reached the present invention.